Can you find out the missing number in the grid?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

Replace the question mark with the correct number in below Picture:

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

The below given figure comprises of a pattern through which you can determine the missing letter. Can you push your mind to find the pattern and add the missing letter?

I am the first thing you need while camping.
I am always with the person named Marcos Valencia and Carrick.
But Pogba Zlatan and Rooney think I am wasteful and do not need me.
I am the second to the last thing to add when you are making a patch.

What am I?